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Topic: preparation of standards for AA or ICP  (Read 3188 times)

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Offline largo3po

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preparation of standards for AA or ICP
« on: August 14, 2011, 02:33:34 PM »
How do you prepare a 5ppm yttrium standard from yttrium nitrate.

Offline marquis

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Re: preparation of standards for AA or ICP
« Reply #1 on: August 22, 2011, 11:18:15 AM »
The manuals that come with the instrument can give you many of the answers.  I haven't worked with yttrium, but I can give you the basic approach.

Generally, a stock solution (typically 1000 ppm as the metal, not the nitrate) is made up.  The salt is put in a 1L volumetric and a dilute acid (typically 1 percent nitric acid) is added to dilute to volume.  This solution is often given a shelf life of 1 year.

The dilute standard is prepared by diluting the stock solution.  One method for a 5 ppm solution would be to pipet 1 ml of 1000 ppm stock solution into a 200 ml volumetric.  Then dilute to volume with 1 percent nitric acid.  These solutions usually have a shelf life of 1 month.

The 1000 ppm (or micrograms per ml) is as yttrium, not as the nitrate.  You need to do the stoichiometry to get to the amount of nitrate needed.  Please be careful.  Many nitrates are actually hydrates of nitrates.  This can majorly mess up your calculations.  Drying your standard is usually a good idea (say at 110 degrees C). It is also a good preventative measure as long as the salt is stable.

Good luck.
 

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